1. Field of the Invention
The present invention relates to a plasma display device and a method of driving the same.
2. Discussion of Related Art
A plasma display device is a flat panel display device that can display characters or images using a gas discharge plasma wherein, according to the size of the display panel, more than several hundreds of thousands to several millions of pixels are arranged in a matrix format.
A conventional plasma display device is driven by dividing one image frame into a plurality of subfields, and gray levels are displayed by the combination of the subfields. Each subfield includes a reset period, an address period, and a sustain period.
As the number of subfields in the image frame is increased, a false contour, which is an important problem with the image quality of a PDP, can be reduced. Accordingly, studies continue to search for a method for increasing the number of subfields in order to reduce a false contour, as do other various studies for securing an operation margin in driving of a plasma display device. Among others, one is a method using a ramp reset waveform.
When using a ramp reset waveform, a falling ramp reset waveform is applied in a state where plenty of wall charges are accumulated on the whole panel using a weak discharge according to the application of a rising ramp reset waveform, so that only wall charges that are proper for an address operation in a subsequent address period are retained, and the remaining wall charges are erased, making it possible to perform a low voltage address operation.
Among driving signals for driving a plasma display panel, in particular, a scan electrode driving signal has a very complicated waveform including an erase waveform in an erase period, a reset waveform in a reset period, an address waveform in an address period, and a sustain waveform in a sustain period. In the case of the reset waveform, its voltage falls from a very high electric potential to a ground electric potential or an electric potential close to ground, so the difference between the starting electric potential and the ending electric potential of the scan electrode during the time its voltage falls is very large, causing a problem in that its current can stress the driving circuit.